chore(ci): Update Claude Code workflow configuration

- Upgrade actions/checkout to v6
- Add Go setup step with go-version-file
- Update golangci-lint to v2.8.0
- Update task to v3.45.5
- Switch claude-code-action from @beta to @main
- Migrate to new claude_args and settings format
- Add additional coding style instructions

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: edenreich

.github/workflows/claude.yml

@@ -31,54 +31,38 @@ jobs:
       actions: read
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 1
 
+      - name: Set up Go
+        uses: actions/setup-go@v6.2.0
+        with:
+          go-version-file: go.mod
+          cache: true
+
       - name: Install golangci-lint
         run: |
-          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b /usr/local/bin v2.4.0
+          curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/master/install.sh | sh -s -- -b /usr/local/bin v2.8.0
 
       - name: Install task
         run: |
-          curl -s https://taskfile.dev/install.sh | sh -s -- -b /usr/local/bin v3.43.3
+          curl -s https://taskfile.dev/install.sh | sh -s -- -b /usr/local/bin v3.45.5
 
       - name: Run Claude Code
         id: claude
-        uses: anthropics/claude-code-action@beta
+        uses: anthropics/claude-code-action@main
         with:
           claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
           additional_permissions: |
             actions: read
           use_commit_signing: true
           base_branch: main
-          branch_prefix: 'claude/'
-          custom_instructions: |
-            IMPORTANT: You must NEVER push directly to the main branch. Always:
-            1. Create a new feature branch (claude/feature-name)
-            2. Make your changes on the feature branch
-            3. Open a pull request to main
-            4. Wait for review and approval before merging
-
-            COMMIT MESSAGE FORMAT: Always use conventional commits with capital letters. 
-            Follow the format: "type(scope): Description" where the description starts with a capital letter.
-            Examples: "feat(a2a): Add retry mechanism for agent connections", "fix(auth): Resolve token validation issue"
-
-            Follow the development workflow specified in the coding instructions.
-
-            IMPORTANT: You never use interface{} type for generics - if you really have to use any.
-          mcp_config: |
+          branch_prefix: "claude/"
+          claude_args: |
+            --allowedTools "Bash(task:*),Bash(go:*),Bash(gh:*),Bash(git:*)"
+            --mcp-config '{"mcpServers":{"context7":{"command":"npx","args":["-y","@upstash/context7-mcp@latest"],"env":{}}}}'
+          settings: |
             {
-              "mcpServers": {
-                "context7": {
-                  "command": "npx",
-                  "args": ["-y", "@upstash/context7-mcp@latest"],
-                  "env": {}
-                }
-              }
+              "systemPrompt": "IMPORTANT: You must NEVER push directly to the main branch. Always:\n1. Create a new feature branch (claude/feature-name)\n2. Make your changes on the feature branch\n3. Open a pull request to main\n4. Wait for review and approval before merging\n\nIMPORTANT: Always add a new line at the end of each file and follow the coding style guidelines.\n\nVERY IMPORTANT: You DO NOT care about backward compatibility - if you DO NOT need the code, simply delete it.\n\nVERY IMPORTANT: You DO NOT add inline comments above code inside of a function body - docblocks are ok for function and types signatures.\n\nIMPORTANT: You never use interface{} type for generics - if you really have to use any.\n\nCOMMIT MESSAGE FORMAT: Always use conventional commits with capital letters.\nFollow the format: \"type(scope): Description\" where the description starts with a capital letter.\nExamples: \"feat(a2a): Add retry mechanism for agent connections\", \"fix(auth): Resolve token validation issue\"\n\nFollow the development workflow specified in the coding instructions."
             }
-          allowed_tools: |
-            Bash(task:*)
-            Bash(go:*)
-            Bash(gh:*)
-            Bash(git:*)